About the Base64 Decoder
Decode Base64 or URL-safe Base64 back to readable text, with validation.
Also known as: decode base64, base64 to text, base64 decoder online.
How to use this calculator
- Enter base64 to decode.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
Every 4 Base64 characters decode back to 3 bytes
Worked example
Using the values pre-filled in the calculator above:
- Base64 to decode: SGVsbG8sIFdvcmxkIQ==
the calculator returns:
- Decoded text: Hello, World!
- Decoded size: 13 B
- Encoded size: 20 B
- Characters: 13